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Portal:Cloud VPS/Admin/Hiera

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Revision as of 13:31, 16 April 2021 by imported>David Caro (→‎Precedence of hiera keys)
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This page contains information on how hiera data is managed in Cloud VPS, which is a bit different from the main production hiera/puppet workflow.

Precedence of hiera keys

Hiera keys may come from different backends, not only puppet hieradata files.

You can set hiera data by using Horizon or through diverse yaml-files in the operations/puppet and labs/private git repos. You can see the exact, always up-to-date resolution order at [2].

By default the hierarchy is searched using the following list top to bottom with a first match win policy. Also note the following considerations when reading this list

  • cloudlib::httpyaml: is a custom backbend to pull data from to Horizon(either at the instance level, prefixes, or project level).
  • /etc/puppet/hieradata/: this is a checkout of the operations/puppet git repo
  • /etc/puppet/private/hieradata: this is a checkout of the labs/private git repo
  • /etc/puppet/secret/hieradata: this is a directory on the stand-alone puppet master which doesn't exist by default
  • %{::wmcs_deployment}: This refers to the openstack deployment currently eqiad1 or codfw1dev
  • %{::labsproject}: This refers to the openstack project e.g. deployment-prep
  • %{::hostname} This refers to the instance name e.g. tools-mail.

The following is a dump as of 2021-03-24.

- cloudlib::httpyaml
- "/etc/puppet/hieradata/cloud/%{::wmcs_deployment}/%{::labsproject}/host/%{::hostname}.yaml"
- "/etc/puppet/hieradata/cloud/%{::wmcs_deployment}/%{::labsproject}/common.yaml"
- "/etc/puppet/hieradata/cloud/%{::wmcs_deployment}.yaml"
- "/etc/puppet/secret/hieradata/labs/%{::labsproject}/common.yaml"
- "/etc/puppet/secret/hieradata/%{::labsproject}.yaml"
- "/etc/puppet/secret/hieradata/labs.yaml"
- "/etc/puppet/private/hieradata/labs/%{::labsproject}/common.yaml"
- "/etc/puppet/private/hieradata/%{::labsproject}.yaml"
- "/etc/puppet/private/hieradata/labs.yaml"
- "/etc/puppet/hieradata/common.yaml"
- "/etc/puppet/secret/hieradata/common.yaml"
- "/etc/puppet/private/hieradata/common.yaml"

Note that providing Hiera settings per role is not possible on Cloud Services.

Only users with the projectadmin role can edit hiera data in Horizon and on Wikitech. Everyone can propose a patch in gerrit to change the hiera data in git, which can then be merged by all of SRE/Ops.

puppetmaster configuration

In order to select a backend/source for hiera data, puppetmasters have a /etc/pupppet/hiera.yaml configuration file with several backends in order, for example:

tools-puppetmaster-02:~# cat /etc/puppet/hiera.yaml
  - httpyaml
  - mwyaml
  - nuyaml

In the example above:

  • nuyaml == local config files
  • mwyaml == wikitech
  • httpyaml == data that horizon writes on the puppetmaster

Puppet enc system

The enc mechanism is a custom made API that serves up hiera config (it's what horizon talks to). See the image to the right for a quick overview.


This web service makes two types of endpoints accessible to different instances, one with read-write permissions and one with only read ones.

It uses a database on db01.cloudinfra.equiad.wmflabs to store the hiera and roles information. The code for the service is here.

Read endpoint

The read only endpoint (referred to as labspuppetbackendgetter in many places), is hosted by nginx, on cloud-puppetmaster-03 (when writing this), listening on port 8100 (http) and 8143 (https).

It's ensuring read only by declining any non GET http request.

Read-write endpoint

The read-write one is hosted directly to uwsgi, open on the same host on port 8000.


There's a small cli that will allow interacting with the enc api installed on all the control nodes (cloudcontrol*):

root@cloudcontrol1003:~# wmcs-enc-cli --help
 usage: wmcs-enc-cli [-h] [--enc-url ENC_URL]
                     [--openstack-project OPENSTACK_PROJECT]
                     [params [params ...]]
 positional arguments:
   params                Any parameters needed for the action chosen.
 optional arguments:
   -h, --help            show this help message and exit
   --enc-url ENC_URL     Full url to the enc, for example
   --openstack-project OPENSTACK_PROJECT

The code for it is hosted here.


This is a cli that puppet runs to retrieve the actual node ENC data [1]. It's a wrapper on top of labspuppetbackend that just transforms the output format to something puppet understands.

The code for it is hosted here. Note that it uses the configuration file /etc/puppet-enc.yaml to retrieve the host for the labspuppetbackend service.

Wikitech integration

Our intention is to kill the wikitech hiera keys definitions. But wikitech has editing history and Horizon doesn't (phab:T153036).

See also


  1. [1]Puppet external node classifier docs